I wonder the same thing.

Apple's MO is to make a premium version of a product and sell a huge quantity of them, and ideally it's a new product category.

Right now there IS a category of vehicle that we don't have in the USA, the cheap small electric cars that have taken over in China.

I could see semi-plausible arguments for mass adoption of those in the USA, as secondary cars for short errands and beginner drivers, and if they were cheap.

But Apple's move is to sell the nicest, most expensive version of a product. It's sort of what their position in the market demands. I don't see any way to put those requirements together in a vehicle, especially considering how we can't import cars from China.